Infection with Animal Helminths as a Factor in Causing Poliomyelitis and Epilepsy

Abstract

By use of a skin-sensitivity test, evidence of infection with toxocariasis has been found in 7 (2.1 %) of 329 apparently healthy persons, in 26 (13.6%) of 191 persons who had had poliomyelitis, and in 26 (7.5 %) of 349 sufferers from epilepsy. It has been confirmed that the reservoir of infection among dogs and cats in the London area is considerable, 21.3% of dogs and 21% of cats having been found to have ova of T. canis and T. cati respectively in their faeces. It is postulated, and evidence is given to support the view, that larvae of T. canis and T. cati in their migration from the lumen of the alimentary tract to the blood and tissues, may carry with them bacteria, viruses, and other infective agents, and that in this way some patients have been infected with poliomyelitis. The larvae do not usually mature in man, but, after wandering in the tissues, die, and a focus of granulomatous tissue reaction forms around their disintegrating bodies. When larvae reach the brain, as they have been shown to do, this process may cause epilepsy. The toxocaral skin test has been found to be positive four times more frequently in epileptic persons than in healthy controls. It is apparent from this and earlier works that dogs and cats may constitute a considerable public-health hazard. This study was made possible by a grant from the Medical Research Council, to whom we express our thanks. We are grateful to Lord Brain for helpful suggestions, for his interest in the work, and for suggesting Lingfield as a centre for the investigations on epilepsy, and to Dr. W. W. Gooddy for facilities in the Department of Neurology, University College Hospital. We also thank Sir Herbert Seddon for his help in gaining access to patients who had had poliomyelitis and to the London County Council for some similar facilities. We acknowledge much valuable technical assistance by Mr. A. I. Shah, and are grateful for the grant from the Hospital for Tropical Diseases Research Fund, which made it possible to employ him. © 1966, British Medical Journal Publishing Group. All rights reserved.